Effects of alpha-lipoic acid on ischemia-reperfusion-induced renal dysfunction in rats.

We investigated whether alpha-lipoic acid (alpha-LA), an antioxidant, attenuates the ischemia-reperfusion (I/R)-induced dysregulation of these transporters. Both renal pedicles of male Sprague-Dawley rats were clamped for 40 min. alpha-LA (80 mg/kg) was administered intraperitoneally before and immediately after induction of ischemia. After 2 days, the expression of aquaporins (AQPs), sodium transporters, and nitric oxide synthases (NOS) was determined in the kidney by immunoblotting and immunohistochemistry. The expression of endothelin-1 (ET-1) mRNA was determined by real-time PCR. Activities of adenylyl cyclase and guanylyl cyclase were measured by stimulated generation of cAMP and cGMP, respectively. The expression of AQP1-3 as well as that of the alpha(1)-subunit of Na-K-ATPase, type 3 Na/H exchanger, Na-K-2Cl cotransporter, and Na-Cl cotransporter was markedly decreased in response to I/R. The expression of type VI adenylyl cyclase was decreased in I/R-injured rats, which was counteracted by the treatment of alpha-LA. AVP-stimulated cAMP generation was blunted in I/R rats and was then ameliorated by alpha-LA treatment. alpha-LA treatment attenuated the downregulation of AQPs and sodium transporters. The expression of endothelial NOS was decreased in I/R rats, which was prevented by alpha-LA. The cGMP generation in response to sodium nitroprusside was blunted in I/R rats, which was also significantly prevented by alpha-LA. The mRNA expression of ET-1 was increased, which was recovered to the control level by alpha-LA treatment. In conclusion, alpha-LA treatment prevents I/R-induced dysregulation of AQPs and sodium transporters in the kidney, possibly through preserving normal activities of local AVP/cAMP, nitric oxide/cGMP, and ET systems.

A case of malignant otitis externa caused by Candida glabrata in a patient receiving haemodialysis.

A 74-y-old male receiving haemodialysis presented with right-sided otalgia, otorrhoea and diffuse swelling on the right external auditory canal. Following an initial successful treatment with prolonged intravenous antibiotics, the patient relapsed with a secondary infection in the same site due to Candida glabrata. We report an unusual case of malignant otitis externa caused by the fungus C. glabrata.

SIADH associated with prostate cancer.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common disease leading to hyponatremia, and it is characterized by an inappropriately elevated serum ADH level relative to serum osmolality. This syndrome may occur in a variety of clinical settings including malignancies. However, it is rarely observed in association with prostate cancer. Moreover, its pathogenesis and clinical characteristics have not been completely understood. We report a case of SIADH associated with prostate cancer in a 64-year-old male patient with a literature review.

Relationship between the serum parathyroid hormone and magnesium levels in continuous ambulatory peritoneal dialysis (CAPD) patients using low-magnesium peritoneal dialysate.

BACKGROUND: Patients on continuous ambulatory peritoneal dialysis (CAPD) have increased risk of low-turnover bone disease and relative hypoparathyroidism. Recently, it has been believed that magnesium plays an important role in regulating secretion of parathyroid hormone (PTH). The aim of this study was to evaluate the relationship between serum PTH and serum magnesium as a factor increasing the frequency of relative hypoparathyroidism. METHODS: We analyzed the data of 56 patients who had been on CAPD for more than 6 months without any significant problems. No patient had been previously treated with vitamin D or aluminum hydroxide. The patients had used peritoneal dialysate with the magnesium concentration of 0.5 mEq/L. Biochemical parameters, such as BUN, creatinine, alkaline phosphatase bony isoenzyme, total protein, albumin, total calcium, ionized calcium and intact parathyroid hormone level were measured. RESULTS: The mean serum magnesium level was 1.99 +/- 0.36 mEq/L. Among total 56 patients, 15 patients (26.8%) showed hypermagnesemia (serum magnesium > 2.2 mEq/L) and 5 patients (8.9%) showed hypomagnesemia (serum magnesium < 1.6 mEq/L). Among all 56 patients, serum iPTH (intact PTH) level was not correlated with serum magnesium level. However, it was inversely correlated with serum total calcium and ionized calcium levels, respectively (r = -0.365, p = 0.006; r = -0.515 p < 0.001). Among 49 patients whose serum iPTH level was less than 300 pg/mL, serum iPTH level was inversely correlated with serum magnesium level (r = -0.295, p = 0.039) and inversely correlated with serum total calcium and ionized calcium levels, respectively (r = -0.546, p < 0.001; r = -0.572 p < 0.001). Among 49 patients whose serum iPTH level was less than 300 pg/mL, lower iPTH group (serum iPTH < 120 pg/mL) showed higher serum magnesium level (p = 0.037), higher serum total calcium level (p < 0.001) and lower bone isoenzyme of alkaline phosphatase level (p < 0.001) than those of higher iPTH group (120 pg/mL < or = serum iPTH < 300 pg/mL). CONCLUSION: Among the CAPD patients whose serum iPTH level was less than 300 pg/mL, there was a significant inverse correlation between serum iPTH level and serum magnesium level. This study indicates that not only serum calcium level but also serum magnesium level are important in the regulation of serum iPTH levels of CAPD patients who have been dialyzed by low-magnesium peritoneal dialysate.